How Much Does It Cost to Replace 12 Windows?
See new windows on your own house
Upload a photo of the front. We will find the windows on it, size them against your front door and price them, then ask about the back and sides — add a second photo, or just tell us the number.
Free · No measurements · No sales call unless you ask
Your original photo isn’t stored. See how your photo is used →
Twelve windows, and either side of it
| Windows | Estimated cost fitted, inc VAT |
|---|---|
| 10 | £9,211 – £16,747 |
| 11 | £10,050 – £18,272 |
| 12 | £10,889 – £19,798 |
| 13 | £11,728 – £21,323 |
| 14 | £12,566 – £22,848 |
What moves the price of twelve windows
Window size first: twelve windows on a detached house usually include two or three large ones downstairs, and a large window costs roughly twice a small one.
Then how many open, the material (uPVC or aluminium), the style (casement, flush or sash), and access — on a detached house more of the twelve are upstairs, and upstairs windows need a tower or, on a tall house, scaffolding. VAT is in every figure.
Example: a 4-bed detached
Twelve windows in white uPVC: £10,889 to £19,798 fitted, inc VAT. The same twelve in aluminium: £13,294 to £24,171.
What is included in these prices
Supplying and fitting the new windows, taking out and taking away the old ones, and sealing and making good around each new frame. VAT is in every figure.
Access for upstairs windows is included where the estimate needs it (£936 for a tower), and small jobs carry a minimum charge of £1,140. Not included: new sills or lintels where the old ones have failed, internal decorating, and anything structural.
Planning estimate or quotation?
Every figure on this page is a planning estimate: what a job like this typically costs, for budgeting and for judging the quotes you get. It is not a quotation. A quotation comes from an installer after a survey, when the exact sizes, specification and condition of your house are known.
Facet Pro narrows the estimate to your own house from a photograph of the front — the windows it can see, the wall it can measure against your front door — and says which parts are measured and which are estimated for your house type. Your installer confirms the figure on survey.
Common questions
How much does it cost to replace 12 windows?
About £10,889 to £19,798 fitted, inc VAT, for twelve uPVC casements on a detached house.
How long does it take to fit 12 windows?
Usually two days for a fitting team, sometimes three if several are large or hard to reach.
Is it cheaper per window to do all twelve?
Yes, per window: access and setting up are paid once across more windows.
Facet Pro is in beta. Our measurement of wall area from a photograph is still being calibrated against surveyed properties, so treat wall and roof figures as indicative and window figures as a guide.
Don’t estimate your house from an average.
Upload a photo and see yours. Every figure above is a typical house. Start with one photograph of the front and we will find your windows, doors, roof and walls, estimate your wall area, and price your own elevation.
Free to try · No measurements · No sales call unless you ask
Your original photo isn’t stored. See how your photo is used →
These are planning estimates — not a quotation, and not a survey. Windows and doors: what these jobs actually sell for, from 24 years of selling them, checked against current UK prices. Walls, roof and roofline: UK material and labour rates, with scaffolding, waste and VAT. What you pay depends on your own house and, more than anything else, on which company quotes it. Your installer confirms the figure on survey.